if you don’t have a PayPal account, you should process your credit card
payment via the PayPal platform. This makes sense if you don’t
know/trust the payment provider from the merchant where you want to buy
something. What if this merchant doesn’t offer the PayPal option on his
website? In most cases companies having a Paypal account, just ask the
merchant, if he want to make a sale, he will offer this payment method
PayPal is also great if you don’t like to show a merchant your credit card details. In several countries it’s possible to pay by PayPal in real-time even if you need to fund your account from your bank account. PayPal is also some kind of online wallet, for example if you sell something on eBay and you get paid via PayPal. Just keep that money in your account and use it for later purchases. If you buy something on eBay and you pay via PayPal, you get some buyer protection. If the seller doesn’t send you the goods your paid for and he can’t proof the successful shipment, Paypal will refund your money.
As a shop holder you should always offer PayPal payments. Using PayPal as payment option on your e-commerce site enables additional payment methods: MasterCard, VISA and many other cards (depends on the buyer’s country). Since the funding methods are different for different countries, PayPal payments are the solution to offer many payment options. Some PayPal payment options for your website are:
For all these payment options is an API system available.
Most of the PayPal features require some setup or you need to add some code (or button) on your website. What if you just need to send a payment request to someone (without knowing his PayPal address or you need just a link that someone can pay you with his credit card? For Microsoft Outlook users is on the PayPal website a plugin available which acts like a kind of wizard that creates the button code you can place into your email.
SIMPAY offers functions where the PayPal payment request is created on-site in a pre-defined form and where the user can send a unique link via e-mail or an instant message system. It’s also possible to e-mail a payment request for recurring payments.
Another great service is FundRazr, they created, together with PayPal, a Facebook application which enables the user to setup a gadget that shows the “charity” and all related information. Other Facebook members will see the gadget on the wall from the fund raiser and are able to send him money via PayPal or they share the gadget on their own wall.
Source : http://www.web-development-blog.com/archives/paypal-payment-tools-information-and-resources/